It has been shown that L. pneumophila has evolved very quickly in the period analysed (1999-2010) by the exchange of genes with other strains of Legionella. Different phenomena of recombination between them have occurred, and these exchanges of genetic material are responsible for 98% of the observed genetic changes. Moreover, these changes have occurred in a very short period of time for these types of processes. It should be noted that these recombination events don't affect the resistance of the Legionella as this is a sensitive bacterium to current antibiotics and patients respond well to the medical treatment.